Clockwork Pony (CR 3)

Medium Construct
Alignment: Always neutral
Initiative: +0(Dex); Senses: darkvision 60 ft., low-light vision, Listen +0, and Spot +0

AC: 17 (+0 Dex, +7 natural), touch 10, flat-footed 17
Hit Dice: 6d10+20 (53 hp)
Fort +2, Ref +2, Will +2
Speed: 40 ft.
Space: 5 ft.; Reach 5 ft.
Base Attack +4; Grapple +8
Attack: Melee: 2 hooves +8 each (1d4+4)
Special Attacks/Actions:
Abilities: Str 18, Dex 10, Con -, Int -, Wis 10, Cha 1
Special Abilities: Immune: construct immunities
Special Qualities: construct traits, rider response, upgrades
Skills: Jump +8, Listen +0, and Spot +0
Climate/Terrain: Any, with rider
Organization: None, inert without rider

Source: Monster Manual IV

Rider Response (Ex): A clockwork steed is built to respond to physical commands given to it by a rider holding its reins or guiding it with the knees. A riderless clockwork steed immediately stops and stands motionless, regardless of threats to itself, until mounted by a rider. A clockwork steed also stops and stands still if its rider becomes unconscious, stunned, paralyzed, dead, or otherwise unable to function.

A clockwork steed cannot be taught tricks like a real horse or pony. A rider can direct it to move and attack foes, just like a war-trained mount, but cannot spur it to greater speed.

Upgrades (Ex): The creator of a clockwork steed can imbue it with more abilities at greater expense. See For Player Characters (page 33, MM4) for more information.